1. Technical Field of the Invention
The present invention relates to a multi-cylinder engine with a cylinder pausing function, in which a valve chamber is formed between a cylinder head and a head cover of an engine body having a plurality of cylinders. A valve-actuating mechanism is accommodated in the valve chamber in order to selectively operate intake and exhaust valves in the cylinder head. A hydraulically-operated valve-pausing mechanism is capable of suspending operation of at least one of the intake and exhaust valves of one or more of the cylinders, depending on an operation state of the engine, such that the suspended valve is held in a closed state in the valve-actuating mechanism. A hydraulic-pressure control device is disposed on the engine body for controlling hydraulic pressure supplied to the valve-pausing mechanism.
2. Background Art
A multi-cylinder engine is known in which the hydraulic pressure of a valve-pausing mechanism, disposed in a valve-actuating mechanism, is selectively controlled to temporarily suspend operation of at least one intake valve or exhaust valve of one or more cylinders such that the at least one of the intake and exhaust valves is held closed, whereby an operation of a part of the cylinders is temporarily suspendable, depending on an operation state of the engine.
Examples of this known type of engine are described in published Japanese Patent Document JP-A No. 2000-205038 (Patent Document 1) and published Japanese Patent Document JP-A No. 2006-283578 (Patent Document 2). In an arrangement disclosed in Patent Document 1, a hydraulic-pressure control device is disposed in a rear surface of a cylinder head where a plurality of intake ports are disposed, so as to place the hydraulic-pressure control device near a valve-pausing mechanism. In an arrangement disclosed in Patent Document 2, a hydraulic-pressure control device is disposed in an upper surface of a head cover.
In each of the above-referenced arrangements, the hydraulic-pressure control device is disposed in an external surface of the cylinder head or the head cover, and thus the hydraulic-pressure control device protrudes from the external surface of the cylinder head or the head cover. Hence, in the arrangement of Patent Document 1, the hydraulic-pressure control device limits freedom of design for positions of the intake ports and an air intake system, and in the arrangement of Patent Document 2 the hydraulic-pressure control device limits a position of a member disposed above the head cover, such as a fuel tank.